#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/ssl.h>
#include <stdio.h>
#include <string.h>

int padding = RSA_PKCS1_PADDING;

RSA *createRSA(unsigned char *key, int public)
{
    RSA *rsa = NULL;
    BIO *keybio;
    keybio = BIO_new_mem_buf(key, -1);
    if (keybio == NULL) {
        printf("Failed to create key BIO");
        return 0;
    }
    if (public) {
        rsa = PEM_read_bio_RSA_PUBKEY(keybio, &rsa, NULL, NULL);
    }
    else {
        rsa = PEM_read_bio_RSAPrivateKey(keybio, &rsa, NULL, NULL);
    }
    if (rsa == NULL) {
        printf("Failed to create RSA");
    }

    return rsa;
}

int public_encrypt(unsigned char *data, int data_len, unsigned char *key,
                   unsigned char *encrypted)
{
    RSA *rsa = createRSA(key, 1);
    int result = RSA_public_encrypt(data_len, data, encrypted, rsa, padding);
    return result;
}
int private_decrypt(unsigned char *enc_data, int data_len, unsigned char *key,
                    unsigned char *decrypted)
{
    RSA *rsa = createRSA(key, 0);
    int result =
        RSA_private_decrypt(data_len, enc_data, decrypted, rsa, padding);
    return result;
}

int private_encrypt(unsigned char *data, int data_len, unsigned char *key,
                    unsigned char *encrypted)
{
    RSA *rsa = createRSA(key, 0);
    int result = RSA_private_encrypt(data_len, data, encrypted, rsa, padding);
    return result;
}
int public_decrypt(unsigned char *enc_data, int data_len, unsigned char *key,
                   unsigned char *decrypted)
{
    RSA *rsa = createRSA(key, 1);
    int result =
        RSA_public_decrypt(data_len, enc_data, decrypted, rsa, padding);
    return result;
}

void printLastError(char *msg)
{
    char *err = malloc(130);
    ERR_load_crypto_strings();
    ERR_error_string(ERR_get_error(), err);
    printf("%s ERROR: %s\n", msg, err);
    free(err);
}

int main()
{
    char plainText[2048] = "Bye, cruel world...";  // key length : 2048

    char publicKey[] =
        "-----BEGIN PUBLIC KEY-----\n"
        "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAy8Dbv8prpJ/0kKhlGeJY\n"
        "ozo2t60EG8L0561g13R29LvMR5hyvGZlGJpmn65+A4xHXInJYiPuKzrKUnApeLZ+\n"
        "vw1HocOAZtWK0z3r26uA8kQYOKX9Qt/DbCdvsF9wF8gRK0ptx9M6R13NvBxvVQAp\n"
        "fc9jB9nTzphOgM4JiEYvlV8FLhg9yZovMYd6Wwf3aoXK891VQxTr/kQYoq1Yp+68\n"
        "i6T4nNq7NWC+UNVjQHxNQMQMzU6lWCX8zyg3yH88OAQkUXIXKfQ+NkvYQ1cxaMoV\n"
        "PpY72+eVthKzpMeyHkBn7ciumk5qgLTEJAfWZpe4f4eFZj/Rc8Y8Jj2IS5kVPjUy\n"
        "wQIDAQAB\n"
        "-----END PUBLIC KEY-----\n";

    char privateKey[] =
        "-----BEGIN RSA PRIVATE KEY-----\n"
        "MIIEowIBAAKCAQEAy8Dbv8prpJ/0kKhlGeJYozo2t60EG8L0561g13R29LvMR5hy\n"
        "vGZlGJpmn65+A4xHXInJYiPuKzrKUnApeLZ+vw1HocOAZtWK0z3r26uA8kQYOKX9\n"
        "Qt/DbCdvsF9wF8gRK0ptx9M6R13NvBxvVQApfc9jB9nTzphOgM4JiEYvlV8FLhg9\n"
        "yZovMYd6Wwf3aoXK891VQxTr/kQYoq1Yp+68i6T4nNq7NWC+UNVjQHxNQMQMzU6l\n"
        "WCX8zyg3yH88OAQkUXIXKfQ+NkvYQ1cxaMoVPpY72+eVthKzpMeyHkBn7ciumk5q\n"
        "gLTEJAfWZpe4f4eFZj/Rc8Y8Jj2IS5kVPjUywQIDAQABAoIBADhg1u1Mv1hAAlX8\n"
        "omz1Gn2f4AAW2aos2cM5UDCNw1SYmj+9SRIkaxjRsE/C4o9sw1oxrg1/z6kajV0e\n"
        "N/t008FdlVKHXAIYWF93JMoVvIpMmT8jft6AN/y3NMpivgt2inmmEJZYNioFJKZG\n"
        "X+/vKYvsVISZm2fw8NfnKvAQK55yu+GRWBZGOeS9K+LbYvOwcrjKhHz66m4bedKd\n"
        "gVAix6NE5iwmjNXktSQlJMCjbtdNXg/xo1/G4kG2p/MO1HLcKfe1N5FgBiXj3Qjl\n"
        "vgvjJZkh1as2KTgaPOBqZaP03738VnYg23ISyvfT/teArVGtxrmFP7939EvJFKpF\n"
        "1wTxuDkCgYEA7t0DR37zt+dEJy+5vm7zSmN97VenwQJFWMiulkHGa0yU3lLasxxu\n"
        "m0oUtndIjenIvSx6t3Y+agK2F3EPbb0AZ5wZ1p1IXs4vktgeQwSSBdqcM8LZFDvZ\n"
        "uPboQnJoRdIkd62XnP5ekIEIBAfOp8v2wFpSfE7nNH2u4CpAXNSF9HsCgYEA2l8D\n"
        "JrDE5m9Kkn+J4l+AdGfeBL1igPF3DnuPoV67BpgiaAgI4h25UJzXiDKKoa706S0D\n"
        "4XB74zOLX11MaGPMIdhlG+SgeQfNoC5lE4ZWXNyESJH1SVgRGT9nBC2vtL6bxCVV\n"
        "WBkTeC5D6c/QXcai6yw6OYyNNdp0uznKURe1xvMCgYBVYYcEjWqMuAvyferFGV+5\n"
        "nWqr5gM+yJMFM2bEqupD/HHSLoeiMm2O8KIKvwSeRYzNohKTdZ7FwgZYxr8fGMoG\n"
        "PxQ1VK9DxCvZL4tRpVaU5Rmknud9hg9DQG6xIbgIDR+f79sb8QjYWmcFGc1SyWOA\n"
        "SkjlykZ2yt4xnqi3BfiD9QKBgGqLgRYXmXp1QoVIBRaWUi55nzHg1XbkWZqPXvz1\n"
        "I3uMLv1jLjJlHk3euKqTPmC05HoApKwSHeA0/gOBmg404xyAYJTDcCidTg6hlF96\n"
        "ZBja3xApZuxqM62F6dV4FQqzFX0WWhWp5n301N33r0qR6FumMKJzmVJ1TA8tmzEF\n"
        "yINRAoGBAJqioYs8rK6eXzA8ywYLjqTLu/yQSLBn/4ta36K8DyCoLNlNxSuox+A5\n"
        "w6z2vEfRVQDq4Hm4vBzjdi3QfYLNkTiTqLcvgWZ+eX44ogXtdTDO7c+GeMKWz4XX\n"
        "uJSUVL5+CVjKLjZEJ6Qc2WZLl94xSwL71E41H4YciVnSCQxVc4Jw\n"
        "-----END RSA PRIVATE KEY-----\n";

    unsigned char encrypted[4098] = {};
    unsigned char decrypted[4098] = {};

    printf("Source text: \"%s\"\n", plainText);
    printf("Source length: %ld\n", strnlen(plainText, 2048));

    printf("\nPublic Encrypt | Private Decrypt\n");
    int encrypted_length =
        public_encrypt(plainText, strlen(plainText), publicKey, encrypted);
    if (encrypted_length == -1) {
        printLastError("Public Encrypt failed ");
        exit(0);
    }
    printf("Encrypted length: %d\n", encrypted_length);

    int decrypted_length =
        private_decrypt(encrypted, encrypted_length, privateKey, decrypted);
    if (decrypted_length == -1) {
        printLastError("Private Decrypt failed ");
        exit(0);
    }
    printf("Decrypted Text: \"%s\"\n", decrypted);
    printf("Decrypted Length: %d\n", decrypted_length);

    printf("\nPrivate Encrypt | Public Decrypt\n");
    encrypted_length =
        private_encrypt(plainText, strlen(plainText), privateKey, encrypted);
    if (encrypted_length == -1) {
        printLastError("Private Encrypt failed");
        exit(0);
    }
    printf("Encrypted length: %d\n", encrypted_length);

    decrypted_length =
        public_decrypt(encrypted, encrypted_length, publicKey, decrypted);
    if (decrypted_length == -1) {
        printLastError("Public Decrypt failed");
        exit(0);
    }
    printf("Decrypted Text: \"%s\"\n", decrypted);
    printf("Decrypted Length: %d\n", decrypted_length);
}
